/*
 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.oracle.dio.gpio.impl;

import java.util.Enumeration;
import java.util.Hashtable;
import jdk.dio.Device;
import com.oracle.dio.impl.AbstractPeripheral;
import com.oracle.dio.impl.Event;
import com.oracle.dio.impl.EventHandler;
import com.oracle.dio.impl.EventQueue;

abstract class GPIOEventHandler<T extends AbstractPeripheral> implements EventHandler {

    private final Hashtable<T, Object> listeners = new Hashtable<>();
    private static final int QUEUE_BUFFER_SIZE = 4096;
    protected final EventQueue queue = EventQueue.createEventQueue(QUEUE_BUFFER_SIZE);

    protected <U extends GPIOEvent> GPIOEventHandler(Class<U> eventClass) {
        queue.registerForEvent(eventClass, this);
    }

    synchronized void setEventListener(T peripheral, Object listener) {
        listeners.put(peripheral, listener);
    }

    synchronized void removeEventListener(T peripheral) {
        listeners.remove(peripheral);
    }

    public synchronized boolean handleEvent(Event event) {
        GPIOEvent e = (GPIOEvent)event;
        Enumeration<T> peripherals = listeners.keys();
        while (peripherals.hasMoreElements()) {
            T p = peripherals.nextElement();
            if (p.getHandle().getNativeHandle() == e.getNativeHandle()) {
                Object listener = listeners.get(p);
                handleGPIOEvent(listener, p, e);
            }
        }
        return true;
    }

    protected abstract void handleGPIOEvent(Object listener, T peripheral, GPIOEvent event);

    protected static abstract class GPIOEvent extends Event {
        int getNativeHandle() {
            byte[] payload = getPayload();
            int handle = ((0x00ff & payload[0]) << 24) |
                         ((0x00ff & payload[1]) << 16) |
                         ((0x00ff & payload[2]) << 8)  |
                         ((0x00ff & payload[3]));
            return handle;
        }
    }
}
